Eichaed v



@auch gisten atrnt @ffice RICHARD Voss, `or NEW YORK, vN. Y.

Letters Parent Na 72,941, ma Beamter s1, 1867. y

IMPROVED GAR-SPRING.

alge Saphire etant tu in tigen glitters zrteirt mit netting met nt tlge smite.

TO .ALL WHOM IT MAY'CONCERN:

Be it-known that I, RICHARD VOSE, of the city, county, andState of New York, have invented a new and useful Improvement upon the Combination-Spring patented by me, December I'T, 1865; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanyingr drawings, which form a portion of this specification.

'The said patented combination-spring is composed of a spirally-grooved India-rubber or gatta-percheI core, embraced by and combined Awith a coiled metallic spring, substantially as represented inthe said patent.

l present improvement on the aforementioned spring consists in first placing a plain cylinder, Figure 3, of sulphurized 'India rubber or gutta percha, within the coiled metallic portion of said spring, and then, by external and indenting pressure exerted thereupon within the continuous open space between the coils of said spring, producing a spiral groove in'said cylinder, immediately within the said open space, and, by the displacement ofthe material thus produced, also causing a'portion of said cylinder to closely embrace the inner surface of the coils of the said metallic portion of' the spring, thereby producing perfectly-proportioned grooves in the periphery of the gum-elastic core of the spring, and a more perfect combination ot' thev gum-elastic and the metallic portions of the same than can possibly beproduced by any other process.

Thesaid'extcrnal and indenting pressure upon the gum-elastic portion of this .spring may-be exerted in two ways, viz: I

First. An inwardly-grooved, screw-threaded, and properly-proportiond sectional casing, c, may be employed, inthe manner represented in tig'. 2, the said grooves and screw-threads being respectively ot' such pitch and proportions that when the sections of the casing are forcedA together upon th-espiral spring and its plain cylindric core, the inwardly-projecting screw-threads e c of' said casing will penetrate said core, and produce the desired edect thereupon. The sections c c of .said casing may be held together b'y-cmbracing-rings, as shown in the drawings, or b y any other suitable means, Whilst the core et' the spring is subjected to the-heating o1" curing operation.

A Second. The same eii`e'ct upon the core or gum-elastic portion of this spring as that above set forth may also be produced by winding a cord of the proper size into the spiral space between the coils of the metallic portion of the spring, with sucient force to nearly or quite embed it Within the said core, and then subjecting the thus-prepared spring to e. sutliciently high temperature to produce the desired vcuring eiect upon the core thereof; 'Ihe curing of this latter preliminary preparation of mysaid improved combination-spring will vbe more uniformly and more perfectly accomplished if the operation be conducted whilst 'it is enclosed in a tube or a tubular casing.

What I claim as my invention, and desire to secure by Letters Patent, is-e- The within-described improvement on the combination-spring patented by me December 17, 18\5 5, viz: placing a plain cylinder, of sulphurized India rubber or gutta perehawithin the coiled metallic portion ofthe spring, and then grooving said cylinder, andmore perfectly combining it with the said metallic portion ot' the spring, preparatory tosubjecting it to the' requisite curing process, all substantially as herein set forth. The aforegoing specification of my improved method of moulding and curing the spirally-grooved, Ind-iarubber core of the combination-spring, patented by RICHARD VOSE, December 17, 1865, signed June 28, 1867,

' RICHD Voss.

Witnesses A. L. Burning- R. R. Woon. 

